Limited Feasibility of Double Transplant Program: A Multicenter Study on 151 Multiple Myeloma Patients Aged≤65 Years.

High dose therapy represents the gold standard therapy for newly diagnosed multiple myeloma (MM) patients (pts), with no definite agreement about the adoption of single or double transplant. From January 2000 to December 2004, 151 consecutive MM pts aged ≤65 years in stage II, III or I in progression according to Durie-Salmon were enrolled in a multicenter no randomised high dose program including a tandem transplant (Tx1; Tx2). The protocol was designed as follows: 2 pulse-VAD as induction, 2 DCEP to mobilise peripheral blood stem cells (PBSC), double auto-transplant 3-6 months apart each conditioned with high-dose Melphalan at the dose of 200 mg/m². Patients characteristics at the enrolment: males 76 (51%), females 75 (49%), median age 55 (range: 35–65), stage I in progression 26 (17%), stage II 25 (16%), stage III 100 (67%). Response rates after each phase for the evaluable patients are reported in the table below

Patients not addressed to transplant for mobilization failure were only 5%. Most of the patients (75%) collected ≥ 4x10⁶CD34+cells/Kg after each DCEP-cycle which were considered adequate to rescue hemopoiesis after each transplant. The whole protocol was well-tolerated. In particular, no therapy related mortality was associated to pulse-VAD, or DCEP, and no difference between Tx1 and Tx2 as far the transplant related mortality was registered (1.5% after each transplant). Second transplant was not performed in 48 pts for the following reasons: 8 pts (7%) did not collect enough PBSC, 8 pts (7%) have had severe toxicity with the first transplant; 8 pts (7%) underwent allo-TMO; 7 pts (6%) had progressive disease and 15 pts (12%) refused Tx2. Finally only 76 pts (50% of the enrolled pts) completed the program with the second transplant. Analysing data on an intention-to-treat basis, median follow-up was 30 months, median Progression Free Survival (PFS) was 31 months, median overall survival (OS) was not reached. The median Event Free Survival (calculated from the completion of Tx1 to progression or any other event) was 20 months. No difference in terms of PFS and EFS was found comparing pts who finally received only Tx1, with those who completed the protocol (p=0.9; p=0.5). The EFS was not statistically different for patients receiving one or two transplant even when the analysis was performed according to the type of response achieved after Tx1. In conclusion, despite higher percentage of good quality responses (CR+VGPR) can be obtained with 2 transplants with respect to 1 (66% vs 89%) without additional toxicity, no difference in terms of PFS or EFS were observed between the patients who underwent 1 or 2 transplants. Thus, keeping into account the more complex management of patients in a tandem transplant program, it might be more advantageous to perform as initial therapeutic approach, high-dose protocol including only 1 transplant procedure.